


Day 2. Baby Fever

by infinitesheith (swrites)



Series: Trans Sheith Week [1]
Category: Voltron: Legendary Defender
Genre: Alpha Shiro (Voltron), Alpha/Beta/Omega Dynamics, Bottom Keith (Voltron), Breeding, Dirty Talk, Edging, Established Keith/Shiro (Voltron), Established Relationship, Impregnation, Knotting, Knotting Dildos, M/M, Mating Cycles/In Heat, Omega Keith (Voltron), Overstimulation, Shiro (Voltron) Has a Large Cock, Size Difference, Size Kink, Size Queen Keith (Voltron), Top Shiro (Voltron), Trans Keith (Voltron), Trans Male Keith (Voltron)
Language: English
Status: Completed
Published: 2020-03-17
Updated: 2020-03-17
Packaged: 2021-02-28 20:07:25
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,400
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23182993
Author URL: https://archiveofourown.org/users/swrites/pseuds/infinitesheith
Summary: Day 2 prompt for Trans Sheith Week on twitter- baby fever.Omega Keith is in heat and keeps seeing these couples together with babies and gets grumpy because his alpha Shiro won’t come in him (Shiro is scared the knot will break Keith.) So, Keith takes matters into his own hands.
Relationships: Keith/Shiro (Voltron)
Series: Trans Sheith Week [1]
Series URL: https://archiveofourown.org/series/1666627
Comments: 6
Kudos: 403





	Day 2. Baby Fever

**Author's Note:**

> Just a heads up for any trans readers, this fic refers to Keith's genitals as cock, and hole. As a trans person, I have my own personal preferences for how my genitals are referred to, but I know that not everyone is comfortable with what I'm comfortable with, so I tried to find a happy medium! That being said, vaginal penetration is a main theme in this story, so if that triggers dysphoria for you as a trans person, please skip this fic. Keep yourselves safe!

Keith is grumpy. He’s been grumpy for some time now, the mood building over the past several weeks. Every time he’s out in public, he sees bonded pairs together, walking hand in hand, the nurturing smell of life wafting from them. He sees omegas with baby bumps, positively glowing, with their alphas hovering protectively around them, fussing over them. He sees omegas and alphas with infants in their arms, or strapped to them with baby slings. He sees families with toddlers on their hips, cooing over their babies, who grab at their hair, or sweaters, or jacket strings, anything to mouth on. 

Babies are  _ everywhere,  _ and Keith  _ wants. _ He’s been trying to convince his alpha Shiro to have a baby with him for months. It’s not like Shiro doesn’t want kids, Keith knows for a fact that one of Shiro’s biggest dreams is to become a parent. And it’s not like Shiro doesn’t want kids with  _ Keith, _ because Keith knows that Shiro is 100% all in with him. Shiro just got promoted at his work- the previous archivist at the public library retired, and he had been mentoring Shiro for years, so naturally Shiro was the only one he could trust to fill the position. And of course, with a promotion like that comes a substantial pay increase. So money isn’t an issue either. They’re ready  _ now _ , but Shiro keeps waffling. 

After a few weeks of Keith trying to talk him around to it, he finally breaks down and asks why he’s so damn stubborn about this. He wasn’t expecting the answer he got- Shiro’s afraid the knot won’t fit, that he’ll break his little omega, and not in the sexy way. 

Honestly, the thought turns Keith on, more than a little. But he isn’t stupid- he knows that with their size difference, the concern is a relevant one. So, Keith drops the subject and decides to take matters into his own hands.

The next time Shiro heads to work, Keith sets out for the nearest adult store. He takes his time browsing, comparing sizes and prices, and eventually he finds what he’s looking for: a knot training kit. Of course, Keith couldn’t be the only omega in the world with this issue. It’s actually pretty common, according to the clerk who helps him with his purchase.

Keith is diligent and methodical in his training. He spends two hours each day with the knotted toy inside him, moving up a size every week. Shiro notices the increase in the lingering scent of Keith’s slick when he gets home from work, but he doesn’t really question it. They just have a lot more sex. The upside to this (aside from getting to take Shiro’s dick more often) is that it gives Keith time to mentally compare his toys to the real thing, so he knows just how far he has to go to make this dream a reality. 

It takes Keith nearly two months of training to reach his goal. The final size transition is the hardest. It takes several tries each day to get in, and he has to drastically cut down the amount of time he keeps it in before slowly increasing it by increments. Even this toy isn’t as big as Shiro, and Keith struggles for an entire week before finally getting it to fit comfortably. And honestly? The knowledge that even this toy that nearly tears him open isn’t as big as his alpha sends him slipsliding into subspace every time he uses it. His subspace high lasts all day, and Shiro spends extra time cuddling and nesting with his omega as he notices. Keith adores him, he knows he couldn’t have picked a better mate. 

His patience has officially run out, so the day that he’s able to take the knot for the full two hours without discomfort, he decides to enact his plan the very next day. 

He’s told Shiro nothing, of course. Keith knows that Shiro suspects  _ something, _ but he respects Keith’s privacy and trusts him enough to know that when Keith is ready to tell him, he will. But whatever Shiro suspects, nothing prepares him for the sight  _ and god almighty, the scent _ that awaits him when he gets home from work.

Keith’s planned everything about this down to the last detail. He takes the heat inducers his primary care doctor gave him. He spends an exorbitant amount of time grooming. He shaves his legs and trims his pubic hair to perfection, and he uses a pheromone enhancing body scrub in the shower, lathering it over every inch of his body until his skin feels sinfully smooth. He packs together a box of protein bars, chocolate chip cookies, and a plethora of water bottles and sets it neatly beside the bed. He turns off the dehumidifiers, bolts all the windows shut, and spends all day edging himself in every room of the house. Each of the toys in his training kit gets a turn. For his first session, before his shower, he uses the smallest toy in the kitchen, suctioning the toy to the wall before getting on his hands and knees and fucking himself. It’s good, and he nearly comes, but he wants  _ more. _ He needs it. The inducers are starting to kick in. 

Having left the used toy in the kitchen, his second edging session takes place in the living room, with the second smallest toy. He’s planned a schedule for each session, one hour apart, each thirty minutes long. He lays down a towel and splays himself out on the sofa, and he’s wet before his fingers even touch his throbbing dick. Keith hisses in relief, forcing himself to keep a slow pace as he strokes himself to complete hardness. With one finger on either side of his dick, he slowly jacks himself off, letting the scent of his need fill the room. The pleasure comes in sharp spikes that jolt from his cock right up his spine, and when he dips his fingers into the wetness of his hole Keith keens softly. He pushes two fingers in and  _ god _ it feels so good, but it’s not enough, he needs to be stretched. With shaky fingers Keith grips the base of the toy, and he whines in disappointment, but he knows he needs to stick to his plan. He rubs the head of the toy up and down along his slit, and he gasps every time the dildo brushes against his cock, sending white hot skitters of pleasure up his spine. Once the toy is completely drenched, Keith slowly eases it in, and  _ fuuuuck. _ It’s not as thick as he wants, not  _ nearly _ as thick as his alpha, but it’s good enough for now, and Keith pushes the toy inch by inch inside of him until the knot presses firmly against his hole. 

He pulls in a shaky breath, and starts to move it, slowly pulling it all the way out before sliding it back home. When the head pushes against his spot, Keith bites his lip and groans, his eyes fluttering shut. God, he knows he needs to go slow, but he just can’t, he needs it. With one more steadying breath, Keith starts pounding himself, imagining Shiro lifting his legs up and fucking into him with force and every time the toy slams into him he cries out loudly. Hazily, he knows that he can’t come yet, he’s waiting for his alpha, so he holds off his rapidly approaching orgasm for as long as he can, pushing himself to the limit with the toy pounding into him roughly, the knot forcing its way deeper inside him with every thrust until he’s taking all of it. He gets closer and closer to the edge, and right before he’s about to tip over, he stops, legs trembling as he lets the toy fall to the floor between his spread legs, breath coming in ragged pants.    
  
_ Fuck, this is going to be hard. _

His third edging session goes in much the same manner, though this time he’s braced the toy on Shiro’s office chair and lowers himself onto it with a high pitched whine. Keith grips the arm rests tightly as he rides the dildo, whining Shiro’s name every time he lets gravity pull him down roughly onto it. Even with the bigger toy, the knot is sliding in easily now, teasing him as it catches on his hole before forcing its way inside, stretching him. Shiro’s smell lingers here, and Keith’s body responds to it eagerly, providing so much slick that it pools between his legs, dripping onto the floor. By sheer force of will, Keith manages to hold back his orgasm for the full half hour, despite how desperately he’s riding the toy. His skin is coated with a thin sheen of sweat, and his hair is matted to his face by the time he’s done, his legs trembling with exertion. Pulling the toy out of him takes an almost herculean amount of effort; the brunt of his heat is nearly upon him.

Despite his continually building lust and the fog of heat that gets thicker by the minute, Keith manages to stick to the schedule. He edges himself two more times before moving to the main event, first in the bathroom, and then the dining room. Each time he leaves his well-used toys right where they lay once he’s finished with them. He wants Shiro to see every single one as he makes his way to the bedroom, wants him to put together what his omega has been doing all day.

Finally, the final session before Shiro comes home has arrived. Keith’s planned this to the minute, he knows Shiro gets home at exactly the same time every day. He’s planned it so that Shiro will open the door to their apartment and immediately be bombarded by an entire day’s worth of Keith’s desire, the heat causing the scent to linger in every corner of the house. Shiro will follow the scent, and the trail of toys, each getting bigger and bigger before reaching the bedroom, where he’ll see Keith just as he finishes his final edging session, the fattest of the toys fully seated inside him, hole stretched obscenely around the knot. 

It’s hard to wait. Keith’s body is absolutely thrumming with need, his skin aching, his cock hard and his hole dripping with slick, squeezing around a toy that hasn’t been inserted yet. He needs to be full, he needs to be pounded. It’s so hard to remember why he can’t come, he’s fighting off the mindless needy haze that comes with the heat. His eyes are glued to the clock, and each minute that passes feels like an absolute eternity. Finally,  _ finally, _ the clock strikes the designated time, and Keith is nearly tripping over himself in his eagerness. He skips any attempt at foreplay, bracing himself on his knees with his ass on display, in perfect view from the doorway, before lining up the last toy. He rubs it against his soaked slit, whimpering as he feels how much bigger it is compared to the others. Still not as big as his alpha, but this is what he needs to tide him over til Shiro gets home. Unable to wait any longer, Keith pushes the toy inside, with much less care than its predecessors. It burns a bit, but that’s exactly what he needs. Keith’s fingers dig into the mattress as he presses the toy inside, the stretch burning as he takes it inch by inch.

“Shiro,” Keith croaks as the toy slides home, fully seated inside him. “Yeah, Shiro, yeah, so fucking big, alpha.” He whines and begins fucking himself in earnest, not bothering to hold his voice back, too far gone to make any attempt at modesty or decency while he slams the toy in repeatedly, crying out roughly each time it pounds against his spot. “Shiro, god please, yeah,  _ fuck,” _ Keith keens, his vision dimming for a moment as he forces the knot inside him. It almost doesn’t want to, but he’s so slick and his hole is sucking the toy in greedily, and after a few more thrusts it slips in with a lewd squelch. Keith’s whole body is on fire, every muscle tense, every nerve ending bristling. He’s right on the edge and god, if he even breathes he thinks he’ll tip over. He can’t see the clock from where he’s pressed face down into the mattress, he doesn’t know how long he’s got. Time doesn’t matter anymore, he just needs Shiro. “ _ Shiro, hnngh.” _

The omega barely registers the shaky gasp that comes from the doorway, too focused on not coming until Shiro’s with him, but when he hears the low rumble of “Keith, holy  _ fuck,” _ his eyes snap open and he’s coming with a scream. 

His orgasm crashes over him unexpectedly, the deep roll of overwhelming pleasure starting at where his hole is spasming around the thick knotted toy and rapidly spreading until it’s igniting his whole body, waves of white hot pleasure cascading against all his senses and he shudders through it, keening desperately while thick pools of slick gush out around the toy and splatter onto the floor.

Shiro is at his side instantly, one hand in his hair and the other on his hip, and the contact burns but in the absolute best way possible. “Keith, baby, you’re so fucking beautiful, holy shit,” he says, his voice rough and low, and Keith keens wordlessly at the praise. “So this is what you’ve been planning all this time, baby? God, you’re so fucking perfect, my omega, my mate. Let go of the toy, Keith.” 

Keith whines, obeying instantly as he spreads his legs further apart, presenting himself properly to his alpha. The toy stays in place thanks to the flared base, and Shiro swears. “Goddamn, baby,” he growls, and he presses the palm of his hand against the base of the toy, rocking it into Keith slowly, who sags into the bed and cries out. 

“Shiro, please,” Keith slurs, words nearly beyond him at this point. “Please, alpha, breed me, please, I need it, knock me up, need your baby, please pleasepleaseplease-” 

The feral growl he gets in response nearly sends him over the edge again. Shiro is carefully pulling the toy out of him, and Keith whimpers at the loss. 

“Shhh, Keith baby, I got you. I can’t wait, baby, I know you need it, I’m gonna put it in, okay?”

Shiro’s voice is strained, and Keith can tell how hard Shiro is fighting to stay in control, waiting for Keith’s consent before doing anything. Keith’s heart bursts with love, affection curling around the need in his scent.    


“God, Shiro please, need you in me, need you please, please- aah  _ fuck yes yes alpha please-” _ Keith is cut off as Shiro slides in, hot and thick and stretching him, filling him up in exactly the way he needs. Shiro doesn’t ask for any more affirmations from Keith, he knows what his omega needs. He digs his fingers into Keith’s hips hard enough to bruise and starts pounding him, slamming in so deep and so rough that all Keith can do is clutch to the mattress and cry. Keith is sobbing, whining and screaming Shiro’s name, and Shiro is just as lost in him.

“Yeah, baby, my perfect little omega, I’m gonna knock you up, I promise,” Shiro croons as he slams into Keith. “You need this, don’t you, Keith? You need my seed in you, you need my baby, huh?” With every word, Shiro’s voice gets lower and rougher, until it’s barely passable for human. Keith screams in response, coming violently around Shiro’s cock, but Shiro’s not done. He’s going to make good on his promise. He pounds right through Keith’s orgasm, giving him no time to adjust before sending him over the edge again, and again. He only stops when Keith comes so hard he squeezes Shiro out, and even then it’s just to flip his mate over, hook the omega’s legs over his arms, and force himself back in. 

“Keith, you’re so fucking beautiful taking my cock like this, fuck,” Shiro growls, his eyes completely black with lust and Keith looks up at him helplessly through his tears, lost in his heat and his alpha and the thick cock splitting him open. “All desperate and needy and begging for  _ me.”  _

“Yeah, yeah, yeah, Shiro yeah-” Keith whines out, the words barely recognizable. His voice is high and strained and Shiro knows he’s on the edge. 

“Fuck, yeah baby, come on your alpha’s dick, come for me Keith, you’re so fucking perfect, come all over my cock, baby, god yeah. You feel so fucking good, fuck,” Shiro moans loudly as he humps into his omega’s tight hole, and his voice is nearly drowned out by the sound of Keith’s screams as he comes,  _ hard. _ The omega’s hands fly up to Shiro’s shoulders and the alpha hisses as Keith digs his nails in, his back snapping taut as his hole squeezes rhythmically around Shiro’s cock, Shiro’s name the only thing he’s capable of saying. 

“Fuck, baby, yeah just like that, I’m almost there, Keith, almost, I’m so close-” 

Keith screams again, his nails raking down Shiro’s back in bloody lines as the alpha forces his knot in. Keith’s hole almost refuses, but then it gives and Shiro’s sliding fully in, and he’s coming hard. “Keith,” Shiro growls into the omega’s ear as he continues humping roughly, each thrust forcing more of his come into Keith’s womb, until Keith is so full he feels like he’s going to burst.

“Shiro, Shiro, Shiro,” Keith chants, choking on a sob, his nails digging into Shiro’s hips to push him in deeper, to show how badly he needs this. 

“Yeah, baby, I know what you need, I’m knocking you up, I got you, it’s okay,” Shiro murmurs softly, nuzzling into Keith’s neck as his thrusting finally begins to slow. He grinds his hips into Keith’s gently, guiding him through one last orgasm before finally coming to a complete stop. Keith is beyond wrecked, he’s absolutely destroyed. He’s clinging to Shiro, shuddering and choking on sobs, tears flowing freely down his face to stain the bedsheets, and Shiro kisses every inch of exposed skin that he can find. “You’re so perfect, Keith, I’ve got you, baby. You did so amazing for me, I’m so proud of you.”

Keith whimpers softly, burrowing into Shiro’s neck and inhaling his alpha’s comforting scent as the older man pets his hair gently. 

“Good boy, just scent me all you need. I’m right here and I’ve got you, baby,” Shiro says as he nuzzles into Keith’s hair. The omega lets out a wordless noise of confirmation, sniffling into Shiro’s shoulder as his tears finally begin to slow to a trickle.

“Did good?” Keith slurs, nose pressed firmly into the crook of Shiro’s neck. The alpha chuckles affectionately, rubbing a hand up and down Keith’s side. 

“God, baby, you were so beyond perfect, I’ve never come that hard in my life.”

Keith whines softly as Shiro’s cock twitches inside him, the memory of the incredible orgasm trying to stir him back to hardness. Shiro laughs and kisses Keith’s forehead as an apology.

“Sorry, baby, we’re done for now, it’s okay.” Shiro keeps touching every inch of Keith’s skin that he can reach, soothing his strung out omega, and before long Keith relaxes enough to doze off in Shiro’s arms, the alpha’s knot still firmly plugged inside him. Shiro chuckles and shifts his weight so he doesn’t crush the smaller man, and settles in to nap as well. If this breeding takes, Keith’s heat will be broken in a few hours. And if not, they can always go again. 

Shiro sighs softly, watching his peacefully dozing omega through heavy-lidded eyes. He can’t believe Keith went to all this trouble for this. Well, yes he can. Keith is stubborn and persistent, and once he sets his mind to something, he doesn’t stop until he gets it. But it still moves him, how far Keith was willing to go to carry Shiro’s child. 

He kisses Keith’s forehead one last time before drifting off to sleep, his last thought that of Keith, three months pregnant, with a just barely there baby-bump. 


End file.
